This disclosure relates to data processing systems. More particularly, this disclosure relates to branch prediction mechanisms within data processing systems.
It is known to provide data processing systems which include branch prediction mechanisms seeking to predict when branch instructions will be encountered within a program stream and accordingly direct, for example, the prefetch operations and the instruction issue operations so that branch instructions will not result in unnecessary program instruction fetching or incorrect program instructions being issued into an instruction pipeline. The speed and efficiency advantages associated with branch prediction mechanisms justify the resources being dedicated to those branch prediction mechanisms. Accordingly, in an effort to increase the accuracy of branch prediction mechanisms, these have become increasingly sophisticated and in themselves represent a significant overhead in terms of circuit overhead and energy use.